Chromosome Abnormalities & Genetic Counseling

Chromosomal abnormalities cause a variety of commonly known diseases. While some diseases are a result of faulty cell division, other diseases are inherited. Persons who have a chromosomal disorder or have a family history of chromosomal disorders may want to seek genetic counseling before or during pregnancy.

Chromosomal Abnormalities

• Human cells possess 23 pairs of chromosomes that divide during meiosis to create gametes (sperm or egg) with 23 individual chromosomes. Chromosomes are at their most vulnerable during this form of cell division. Problems during cell division include deletion, duplication, inversion or translocation of small sections of genetic material on a single chromosome. In addition, the chromosome pair may not separate, causing a trisomy, or three of the same chromosome, in the resulting embryo.

Common Chromosomal Diseases

• Down Syndrome results from a trisomy of chromosome 21. Prader-Willi results from a deletion on chromosome 15. Females born with only one sex chromosome instead of two are diagnosed with Turner syndrome.

Genetic Counseling

• Genetic counselors interpret genetic information taken from both the parents and/or the fetus. They also take into consideration maternal age, since Down Syndrome occurs more frequently in women over the age of 35. Before conception, your genetic counselor can identify any chromosomal abnormalities and offer advice on conception and provide you with support groups. Post-conception the counselor can explain options for care of the child or termination of the pregnancy.